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USA Opals are found in several areas,
Virgin Valley in Nevada USA.
The area is known for its unusual fire play in wood ,limp casts and bark replacement.
Virgin Valley opals. They are black opals, found in Humboldt County, Nevada. Their black matrix contains stunning flashes of red, blue, purple, and green
There is some opal attached to this specimen. We have taken the photo wet. Great collector’s item.
Virgin Valley opal is believed to be app 14 -15 million years old.
The opal has a tendency to craze when dried too fast as it contains up to 14 % water. We just know we lose most to drying but a small percentage is stable. Some cutters store the opal in mineral oil for a year and change it every 3 months before cutting.
Utah Opal Is known as Bacon Opal or Candy Strip Opal
As these colours are formed in stripes similar to bacon.
Opals can be slightly translucent and can have mixture white,pink,red or yellow stripes.
Opal is hydrated silica
Spencer Opal
Idaho USA,This opal was formed in volcanic rocks around 4 million years ago by geysers.
When a geyser erupted ,the liquid contains tiny spheres of silica would form thin layers of precious opal
The opal colour bar is very thin but ideal to make opal triplets.
This opal can be stabilized as same treatment to Ethiopian opals
Oregon Opals
The opals are found in rhyolite geodes (thunder eggs) in a perlite that has altered to pastel colored clay. The geodes that contain gem-quality opal are only about 10% of the total geodes mined and only about 1% of the geodes contain gem-quality opal with play of color. The remaining geodes contain agate, quartz crystals, or common opal. The geodes vary greatly in size, from a few centimetres in diameter to over a meter
